JP2006062878A - Slurry-like quick setting agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slurry-like quick setting agent having excellent mixing property and dispersibility, hardly causing the separation and deposition of a solid component in a stationary preservation, easily dispersed and returned to the original fluidizing state only by carrying out a relatively moderate stirring even if the separation and the deposition occur by leaving the quick setting agent standing for a long period and capable of giving stable rapid hardening. <P>SOLUTION: The slurry-like quick setting agent contains following (A), (B) and (C) as effective components, wherein (A) is calcium aluminate, (B) is a lower dihydric alcohol and (C) is inorganic powder inactive to the lower dihydric alcohol and having 10 m<SP>2</SP>/g BET specific surface area. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slurry-like hardener that is mixed with cement paste, mortar, concrete, cement-based solidifying agent and the like to obtain fast hardening.

In order to give fast hardening to cement, various quick hardening agents containing fast hardening substances such as aluminum sulfate, alkali aluminate, and calcium aluminate as active ingredients are used. Most of them are in powder form, so they are bulky during storage and transport, are easily weathered and difficult to store for a long time, are scattered during compounding, are difficult to mix uniformly, and bubbles are easily taken into the hydrous kneaded product. There was a problem in work. For this reason, rapid hardening agents that can be stored and used in liquid form have been studied. Since all fast-hardening materials that can be used for cement have hydration activity, it is impossible to maintain a stable property just by liquefying the fast-hardening material with water, and self-curing may occur. Although it is known that a liquid fast-curing agent that suppresses self-curing can be obtained by using a setting retarder such as an organic acid in combination (see, for example, Patent Document 1), it is used to maintain an inhibitory action for a long time. When the amount is increased, the fast-curing performance deteriorates, or curing failure occurs when mixed with cement. Therefore, only those that can withstand short-term storage are practical. Moreover, although a method of liquefying a fast-curing substance with a non-aqueous organic solution is also known (see, for example, Patent Document 2), if the mixture is left for about several weeks, sedimentation accompanying solid-liquid separation proceeds, In a normal stirring operation, it is extremely difficult to return to the original liquid state. For example, in a water-fly ash system, the use of an anti-settling agent such as silica fume (for example, see Patent Document 3), which is known to be effective in suppressing the settling of fly ash, may reduce this phenomenon. is there. However, even when anti-settling agents such as silica fume are used, the anti-settling action can only be maintained for about 200 hours, and after that, in addition to the progress of settling, the tightening of the settling progresses and is stable over a longer period. It was difficult to maintain the fluidity and fast-curing properties.
JP 2003-81664 A Japanese Patent Laid-Open No. 5-97484 JP 2002-68793 A

  The present invention has been made for the purpose of solving the above-mentioned problems related to liquid quick-curing agents. Separation and sedimentation are unlikely to occur. A slurry-like hardener capable of returning to a uniform fluidity state and imparting stable quick hardening is provided.

  In order to solve the problem, the present inventors used calcium aluminate having a strong rapid hardening action as a fast-hardening substance, and started to make a slurry thereof. In addition to being inert to calcium aluminate as a slurry medium, Focusing on aliphatic alcohols from the viewpoint of versatility and cost, among them, when divalent lower alcohol is used in combination with an inorganic powder having a specific specific surface area, separation and sedimentation hardly occur for a relatively long time, and Surprisingly, it has been found that even if separation occurs, sediment tightening hardly progresses over a long period of time, and as a result, even if separation occurs, it can be easily returned to a uniform mixed flow state with simple stirring. The inventor has obtained the knowledge that stable fast-curing properties can be expressed even after being stored for a long period of time, and the present invention has been completed.

That is, this invention is the slurry-like quick hardener represented by the following (1)-(2), and the hydraulic composition represented by (3). (1) A slurry-like hardener containing the following (A), (B) and (C) as active ingredients. (A) Calcium aluminate. (B) Divalent lower alcohol. (C) An inorganic powder having a BET specific surface area of 10 m ² / g or more which is inert to divalent lower alcohols. (2) The slurry-like rapid hardener according to (1), wherein the divalent lower alcohol is ethylene glycol and / or propylene glycol. (3) A hydraulic composition comprising the slurry-like fast hardener of (1) or (2) and cement.

  The slurry-like fast curing agent according to the present invention is excellent in long-term storage and mixing / dispersibility at the time of addition, and does not scatter at the time of addition, and does not easily cause separation of components or settling of solid matter during the storage period. In addition, even if it is in a solid-liquid separation state after being left for a long period of time, the precipitate can be uniformly dispersed with only a slight agitation, and can easily return to the original fluid slurry state. Stable fast-hardness can always be imparted without lowering the performance.

The slurry-like quick hardener of the present invention uses calcium aluminate as a component that imparts quick hardening. Calcium aluminate used in the present invention is a general term for a compound containing CaO and Al ₂ O ₃ as main chemical components, a solid solution, glassy material, or a mixture of these, and has a hydration activity. Not limited. Examples include 12CaO · 7Al ₂ O ₃ , CaO · Al ₂ O ₃ , 3CaO · Al ₂ O ₃ , 11CaO · 7Al ₂ O ₃ · CaF ₂ , 4CaO · 3Al ₂ O ₃ · SO ₃ , and alumina. Cement may be used.

  In addition, the slurry-like hardener of the present invention uses a divalent lower alcohol as a slurry medium. Preferably, one or both of ethylene glycol and propylene glycol are used. In general, when an organic solution is added to a fast-curing substance for cement, the fast-curing property tends to be reduced, but a dihydric lower alcohol does not show a decrease in fast-curing property. On the other hand, monohydric alcohols reduce rapid hardness, and particularly low molecular weight compounds have high volatility and are too low in viscosity, making it difficult to obtain a stable slurry state and poor workability. In addition, trihydric or higher alcohols have high viscosity, making it difficult to uniformly mix with a hardening accelerator and disperse in mortar / concrete. Among dihydric alcohols, alcohols other than lower alcohols such as hexylene glycol are not preferred because of their high viscosity and difficulty in mixing and dispersibility. The divalent lower alcohol used in the present invention does not contain water for preventing alteration of calcium aluminate. By using divalent lower alcohol as a slurry component and using it together with inorganic powder with a specific surface area described later, it is sufficient that the sediment when segregation and sedimentation that easily occurs when stored for a long period of time is tightened and hardened. There is an inhibitory effect. Furthermore, even after long-term storage, precipitates can be easily dispersed by a slight stirring operation such as by stirring for about 1 to 2 minutes using, for example, a commercially available hand mixer or hand scoop, resulting in performance degradation. It can return to a slurry state, without.

In addition, the slurry-like hardener of the present invention also uses an inorganic powder having a BET specific surface area of 10 m ² / g or more which is inert to a divalent lower alcohol. The inorganic powder suppresses solid-liquid separation of the slurry and enables long-term storage. The inorganic powder is not limited as long as it is inert to divalent lower alcohols, but is different from calcium aluminate that is essential for the slurry. In addition, an inorganic powder which does not have hydration activity alone is preferable because it can maintain a stable property for a long period of time. Examples of inorganic powders that can be used in the present invention can include non-hydrated silicate mineral powders such as silica fume, fumed silica, silica stone powder, mullite, alumina powder, limestone powder, etc. good. Among these, the use of silica fume or fumed silica is more preferable. In addition, with an inorganic powder having a BET specific surface area of less than 10 m ² / g, it is difficult to obtain a solid-liquid separation inhibitory effect, and it is difficult to suppress tightening of the separated sediment even when used in combination with a divalent lower alcohol. It is not preferable. The upper limit of the BET specific surface area is not particularly limited, but is preferably about 500 m ² / g from the viewpoint of dispersibility at the time of blending and production cost.

The content of the active ingredient in the slurry rapid hardening agent of the present invention is 1 to 100 weight of inorganic powder having a BET specific surface area of 10 m ² / g or more which is inert to divalent lower alcohols with respect to 100 weight parts of calcium aluminate. Part is preferred. If it is less than 1 part by weight of the inorganic powder, the effect of suppressing the separation hardly appears. Moreover, what is necessary is just to select suitably content of a bivalent lower alcohol in the range used as a slurry state. When a suitable example is shown, it is 20-200 weight part with respect to 100 weight part of calcium aluminates. If it is less than 20 parts by weight, it may not become a slurry, or may become so viscous that it interferes with mixing and dispersibility. If it exceeds 200 parts by weight, the concentration of the fast-hardening component in the slurry becomes too dilute, which is practical. Lack. As a slurrying state of the slurry-like hardener of the present invention, for example, a fluidity such that the viscosity at 5 to 35 ° C. is a value in the range of about 0.01 to 10.0 Psa with a B-type viscometer. What is exhibited is desirable, and what is necessary is just to be able to easily reproduce the fluidity by stirring even when solid-liquid separation occurs.

  Further, unless the effect of the present invention is lost, the slurry-like hardener of the present invention is not limited to contain components other than the above-mentioned effective ingredients, for example, alkali or alkaline earth metal carbonates and dispersants, etc. May be included.

  The manufacturing method of the slurry-like quick hardener of this invention is not specifically limited. In addition, it is desirable that the method of use is not used as it is in a state where a separated sediment is observed, but is used in a slurryed state as described above by stirring as necessary. For example, when this is mixed with mortar or concrete, it can be mixed at any time before water injection, after water injection or simultaneously with water injection.

  Moreover, the hydraulic composition of this invention contains the said slurry-like quick hardener and cement. The cement may be any cement as long as it is hydraulic. For example, ordinary Portland cement, various Portland cements, various mixed cements, and various special cements can be used. In addition, the hydraulic composition of the present invention can also include other than the slurry-like fast hardener and cement within a range not losing the effects of the present invention, for example, aggregate, fiber, pigment, shrinkage reducing agent, expansion Admixtures and materials such as materials, rust preventives, antifoaming agents, air entraining agents, thickeners, water reducing agents (including high performance water reducing agents and high performance AE water reducing agents), dispersants, water retention agents, polymer resins, etc. Water can be mentioned.

  Moreover, it is preferable that content of the said slurry-like quick hardener and cement of the hydraulic composition of this invention will be 2-100 weight part of slurry-like quick hardener with respect to 100 weight part of cement. . When the slurry hardener exceeds 100 parts by weight, the long-term strength may decrease. Moreover, if it is less than 2 weight part, it will become difficult to express quick hardening.

Hereinafter, the present invention will be described in detail by way of examples.
[Preparation of Slurry] Hands for kneading mortar so that the materials selected from A1 to A3, the materials selected from B1 to B6, and the materials selected from C1 to C7 are as shown in Table 1 below. The mixture was mixed for about 5 minutes with a mixer to prepare 1 liter of slurry (invention products 1 to 7, reference products 11 to 18).
A1: Calcium aluminate I (powder in which CaO and Al ₂ O ₃ were mixed at a molar ratio of 12: 7 was heated in an electric furnace at about 1600 ° C. and then gradually cooled in the furnace, and then pulverized. 12CaO · 7Al ₂ O ₃ crystals substantially consist of 100% Brain specific surface area of about 4000 g / cm ² )
A2: Calcium aluminate II (a trial product obtained by heating a powder powder in which CaO and Al ₂ O ₃ are mixed at a molar ratio of 2.2: 1 in an electric furnace to about 1600 ° C. and then dry quenching. Vitrification rate 100 %, Blaine specific surface area of about 4000 g / cm ² )
A3: Alumina cement (manufactured by Taiheiyo Material Co., Ltd.)
B1: Monoethylene glycol (commercially available reagent)
B2: Propylene glycol (commercially available reagent)
B3; Ethyl alcohol (commercially available reagent)
B4: Butyl alcohol (commercially available reagent)
B5: Glycerin (commercially available reagent)
B6; Water (Household water)
C1: Silica fume (BET specific surface area 15m ² / g, made in China)
C2: fumed silica (BET specific surface area 200 m ² / g, manufactured by Nippon Aerosil Co., Ltd.)
C3: Silica stone powder (BET specific surface area 3 m ² / g)
C4: Silica powder (BET specific surface area 0.9 m ² / g)
C5: Aluminum oxide powder (BET specific surface area 13 m ² / g, commercially available reagent)
C6: Limestone powder (BET specific surface area 0.9 m ² / g)
C7; methylcellulose (BET specific surface area 0.2 m ² / g, manufactured by Shin-Etsu Chemical Co., Ltd.)

  [Slurry Properties] For each of the produced slurries, solid-liquid separation occurred with respect to those produced within 5 minutes immediately after production, and those left for 1 week and 3 months (both in a constant temperature room at 20 ° C.). The presence or absence was examined visually. In the investigation on the occurrence of solid-liquid separation, it was judged that solid-liquid separation was “present” if the solid-liquid separation was confirmed by visual inspection. However, those solidified without solid-liquid separation immediately after production were excluded from the investigation target, and solid-liquid separation was judged to be “no” only for those for which solid-liquid separation was not observed without solidification. The results are shown in Table 2. Moreover, the viscosity at 20 degreeC of the slurry within 5 minutes immediately after preparation and the slurry left still for three months from preparation was measured with the B-type viscometer. At the time of measurement, the solid-liquid separation that was confirmed by visual observation was stirred for 1 minute (1100 rpm) with a RYO hand mixer. As for what was done, the slurry viscosity in the state was measured. However, those whose solidification progressed immediately after production without solid-liquid separation or those in which solid-liquid separation was caused and precipitation was tight and stirring was substantially impossible were excluded from the objects of viscosity measurement. The results are also shown in Table 2.

  [Production and characterization of mortar hydraulic composition] Ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd.), fine aggregate (crushed sand from Kokura-minami-ku, Kitakyushu-shi and Noura offshore in Sanuki Gungo, Nagasaki Prefecture) Sea sand = 3/7) and water are added to Hobart mixer at a mixture ratio of fine aggregate / cement (weight ratio) = 3.0 and water / cement (weight ratio) = 0.5. A fresh mortar was prepared by kneading for 10 minutes. The slurry shown in Table 3 was allowed to stand at a temperature of 20 ° C. for 3 months and then stirred for 1 minute with a hand mixer (excluding slurries that cannot be stirred and slurries that cannot be resolved even if stirred). Was added to 100 parts by weight of cement in fresh mortar, and the mixture was further kneaded for 1 minute to prepare a mortar hydraulic composition. With respect to this mortar hydraulic composition, the quick hardening property was evaluated by a finger touch method. That is, the surface of the mortar hydraulic composition that was allowed to stand at a temperature of 20 ° C. for 30 minutes after kneading was strongly pressed with a finger until any of the depression, deformation, or crack occurred, and the depression was depressed for about 10 seconds. The case where neither deformation nor crack occurred at all was judged as “hard”, and the rest was judged as “no”. The evaluation results are also shown in Table 3.

  The slurry-like fast hardener of the present invention can be imparted with quick hardening by being used in cement paste, mortar, concrete, cement-based solidifying agent and the like. It is particularly suitable when it is desired to shorten construction work in a closed space or mixing / kneading work. Also, even if the remaining part is stored for a relatively long time without being used up, a large work load is applied during reuse, and almost no performance degradation such as rapid hardening is observed. It is also suitable for intermittent use in construction and construction.

Claims (3)

Slurry fast hardener containing the following (A), (B) and (C) as active ingredients. (A) Calcium aluminate. (B) Divalent lower alcohol. (C) An inorganic powder having a BET specific surface area of 10 m ² / g or more which is inert to divalent lower alcohols. The slurry-like rapid hardener according to claim 1, wherein the divalent lower alcohol is ethylene glycol and / or propylene glycol. A hydraulic composition comprising the rapid slurry hardener according to claim 1 or 2 and cement.